Tonks + Snape
Yes. I would much rather have delivered my information to Albus and let him dole it out as he wished with no one in the Order knowing my identity. Being known as a member of the Order made it more difficult for me to allay the Dark Lord's suspicions and was more of a hindrance than a help.
Do you have any idea how much maneuvering I had to do after Potter appealed to me for help when he thought Black had traipsed off to the Ministry? Draco was quick to pass that information on to his father and while Lucius was more inclined to use it as blackmail material, he informed Bellatrix about it and it took weeks to recover from her attempts to undermine me.